Ignition distributor

ABSTRACT

An ignition distributor which is particularly suitable for use in high speed engines and rotary engines of the &#39;&#39;&#39;&#39;Wankel&#39;&#39;&#39;&#39; type in which a disc having peripheral discontinuities is rotated on a shaft so that the discontinuities pass between a light source and a photo device so that the light from the light source to the photo device is interrupted intermittently in a predetermined manner, centrifugal advance and retard means being associated with the disc to advance or retard the production of a spark in a sparking plug, the light source and photo device being mounted so as to be movable around the shaft by vacuum advance and retard means, the shaft carrying a distributor arm around which are mounted contacts for connection to the number of spark plugs. In preferred forms of the invention a dwell compensating mechanism is also associated with the disc and a transistorised amplifier trigger unit is mounted within the distributor. In the latter case water or air cooling is provided to restrict the temperature of parts of the distributor. An ignition coil may be provided in the cap of the distributor.

United States Patent [1 1 Trass IGNITION DISTRIBUTOR [76] Inventor: Alan Neville Trass, 44 Moyran Parade, Grays Pt., Wales [22] Filed: Jan. 24, 1972 [21] Appl. No.: 220,067

Primary Examiner-Herman J. Hohauser Assistant Examiner-M. Ginsburg Att0rneyE. F. Wenderoth et al.

[ 1 Oct. 23, 1973 [57] ABSTRACT An ignition distributor which is particularly suitable for use in high speed engines and rotary engines of the Wankel type in which a disc having peripheral discontinuities is rotated on a shaft so that the discontinuities pass between a light source and a photo device so that the light from the light source to the photo device is interrupted intermittently in a predetermined manner, centrifugal advance and retard means being associated with the disc to advance or retard the production of a spark in a sparking plug, the light source and photo device being mounted so as to be movable around the shaft by vacuum advance and retard means, the shaft carrying a distributor arm around which are mounted contacts for connection to the number of spark plugs. In preferred forms of the invention a dwell compensating mechanism is also associated with the disc and a transistorised amplifier trigger unit is mounted within the distributor. In the latter case water or air cooling is provided to restrict the temperature of parts of the distributor. An ignition coil may be provided in the cap of the distributor.

8 Claims, 9 Drawing Figures IGNITION SWITCH PATENTED MT 23 I975 SHEET 10F 2 T0 BATT VIA IGNITION SWITCH 1 IGNITION DISTRIBUTOR The present invention relates to an ignition distributor for internal combustion engines, the principal object of the invention being the provision of an ignition distributor having features which make it particularly suited for use with modern high-speed engines and in particular with rotary engines of the Wankel" type.

The invention consists in an ignition distributor consistingof a body, a drive shaft supported in the body in bearings,'a light source mounted in said body, a photo device mounted adjacent said light source in the path of light therefrom, the light source and the photo device being mounted so as to be movable together about the axis of said drive shaft, a disc mounted on said shaft so that the periphery of the disc rotates between the light source and the photo device, there being discontinuities in the peripheral portion of the disc whereby the path of light from said light source to the photo device is interrupted intermittently in a predetermined manner, centrifugal advance and retard means associated with said disc whereby the disc is rotated in relation to the shaft to an extent related to the speed of rotation of the shaft, a chamber in the body adapted to be connected to the inlet manifold of an internal combustion engine, means in said chamber movable in response to changes in the pressure in said manifold, a connection between said movable means and the light source and the photo device whereby these are moved around said shaft to advance or retard the ignition in relation to said changes in pressure, a distributor arm on said drive shaft, connecting means for connecting an ignition coil to said distributor arm and contact means whereby the electrical output from said ignition coil is delivered in turn to the spark plugs for connection to the spark plugsofan internal combustion engine.

Inorder that the invention may be better understood and put into practice a preferred form thereof is hereinafter described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a sectional elevation of a distributor according to the present invention,

FIGS. 2a, 2b and 2c are a sectional elevation, sectional plan and front elevation respectively of the sensorunit, I I I FIGS. 3a and 3b are respectively a plan and elevation of the trigger plate showing the dwell compensator and advance and retard mechanisms,

FIGS. 40 and 4b are respectively a plan and sectional elevation of a preferred form of advance and retard and dwell compensator mechanisms, and

FIG. 5 is a plan view of an alternative construction. The distributor consists of a body made up of two main parts, a lower part and an upper part 11 the two being secured together by screws 12. The lower part 10 contains bearings 13 for the distributor drive shaft 14, these bearings being of a type that will allow 5 Axial movement of the piston 15 causes rotation of the sleeve 22 through the inclined slot 23. The plate 24 is attached to the sleeve 22 and moves with it and carries the sensor unit 25. The chamber 16 is connected to the engine inlet manifold by the pipe 26 and thus the position of the sensor unit 25 is advanced or retarded in accordance with changes in the manifold pressure.

The chamber 16 is surrounded by an annular passage 27 through which cooling water may be passed or alternatively external cooling fins (as shown at the right of the figure) may be provided around the chamber 16. The purpose of this is to prevent the temperature of this partof the distributor from rising unduly thus enabling a transistorised amplifier trigger unit to be fitted at 28 thus making the distributor self contained.

The sensor unit 25 is shown in FIGS. 2a, 2b and 2c and consists of a light source 3l which may be an incandescent lamp and a photo device such as a photo transistor 32. The light beam is controlled by the small square apertures 33. The fact that the sensor unit is constructedintegrally ensures that the light source and the photo device are correctly aligned and simplifies installation. While an incandescent lamp and a photo transistor are to be preferred, it will be appreciated that any other suitable source of light or photo device may be used.

Between the gap 34 in the sensor unit the trigger plate assembly 35 is rotated. This assembly is attached to the upper end of the shaft 14 and rotates with it. It consists of an upper disc shaped plate 36 and a lower disc shaped plate 37, each having in them four peripheral slots 38 (assuming the distributor is intended for an engine having four cylinders and four sparking plugs). The angular position of the upper plate 36 in relation to shaft 14 is controlled 'by a dwell compensator mechanism 41 and that of plate 37 by a centrifugal advance and retard mechanism 42. Details of these mechanisms may be conventional each consisting of a centrifugal device which acts to rotate the plate in relation to the shaft 14 to an extent depending on the rate of rotation of the shaft. The effect of movement of the plate 37 is to act to advance the spark as the speedof rotation increases. Rotation of the plate 36 controls the effective size of the slots 38 and thus the dwell angle, the arrangement being such thatat idling speeds the width of.

the slots 38 is a minimum, for example 5l0, the width increasing with increasing speed, to permit the ignition coil to just saturate.

FIGS. 4a and 4b show a preferred arrangement incorporating an advance and retard mechanism 42 and dwell compensator mechanism 41. These are constructed in essentially the same manner and it is proposed therefore to describe only the latter in detail, as the parts of this are seen clearly in FIG. 4a.

The mechanism consists of two weights 52, preferably moulded in plastic material of identical shape and weight each of which is carried on a piano wire spring 53, the inner end of which is anchored in the drive shaft 14 and the outer end of which passes through the ring 54 which is attached to the disc 36. As the speed of rotation increases the weights 52 will move outwards deforming the springs 53 and causing the ring 54 and thus the disc 36 to rotate in relation to the shaft 14. Slots 55 and pins 56 limit the extent of rotation of the disc. Control of the disc 37 is effected in a similar manner, the whole mechanism operating as described above to adappropriate radiation.

vance or retard the ignition and to vary the dwell angle with the speed of the engine.

FIG. 5 shows an alternative arrangement in which the rotation of the plates is controlled by balls or rollers 57 which lie between vertical angled plates 58 and piano wire springs 59 extending between the shaft 14 and the ring 60 attached to the upper plate. Slots 61 allow the upper disc to rotate and act to limit the extent of its movement. In this construction a rotational force is applied to the plate through the centrigufal movement of the balls or rollers 57 as the speed of rotation increases, the springs 59 causing the ring 60 to rotate and with it the upper disc. Movement of the lower disc is con'-' trolled in a similar manner.

The distributor may be provided with a simpler arrangement in which the dwell compensator mechanism is omitted. I I

A rotor arm 43 is attached to the upper end of the shaft 14 which is connected through the contact button 44 to the ignition coil 45 which is contained within the cap 46 mounted directly to the upper part 1 l of the distributor body, the coil 45 being wound on a toroidal core 47. Connectors'48 are arranged on the top of the cap 46 for attachment of the ignition leads to the individual spark plugs and these are connected directly to contacts 51 arranged around the upper edge of the upper part 11 of the distributor body.

The majority of the parts of the distributor described above are capable of being moulded in plastic material atlow cost. t

The embodiment of the invention described above is given'by wayof example only and a variety of other forms of construction within the scope of the invention may be devised.

For example, the integral ignition coil in the cap may be omitted and the distributor used with a plain cap in conjunction with a separate coil. The piston operated vacuum advance and retard may be replaced by a vane type as the required operating torque is low. Cooling of the distributor may be effected by passing fil'tered air through it, the'vacuum being provided by the engine I inlet manifold.

invention will occur readily to those skilled in the art.

The term light source" as used in the present specification is to be taken to include any source of radiation whether visible or invisible and the term photodevice" is to be taken to mean a device capable of detecting the I claim: 1. An ignition distributor consisting of a body, a drive shaft supported in the body in bearings, a light source mounted in said body, a photo device mounted adja-.

cent said light source in the path of light therefrom, the light source and the photo device being mounted so as to be movable together about the axis of said drive shaft, a disc mounted on said shaft so that the periphery of the disc rotates between the light source and the 4 photo device there being discontinuities in the peripheral portion of the disc whereby the path of light from said light source to the photo device is interrupted in a predetermined manner intermittently, centrifugal advance and retard -rneans associated with said disc whereby the disc is rotated in relation to the shaft to an extent related to the speed of rotation of the shaft, a chamber in the body spaced from said disc and adapted to be connected to the inlet manifold of an internal combustion engine, means in said chamber movable in response to changes in the pressure in said manifold when said' chamber is connected to said manifold, a connection between said movable means and the light source and the photo device whereby these are moved around said 'shaft to advance or retard the ignition in relation to said changes in pressure, a distributor arm on said'drive shaft, connecting means for connecting an ignition coil to said distributor arm and contact means whereby the electrical output from saidignition coil is delivered in turn to connecting means adapted for connection to the spark plugs of an internal combustion engine.

2. An ignition distributor as claimed in claim 1, wherein thelight source and the photo device are mounted in a fixed relationship in a common housing.

3. An ignition distributor as claimed in claim 1,-

wherein a transistorised amplifier trigger unit is mounted within the distributor and means are provided for cooling parts of the distributor adjacent thereto.

4. An ignition distributor as claimed in claim 1, wherein said disc is madeup of two superimposed discs mounted one above the other, having similarly arranged radial slots constituting said discontinuities, centrifugal advance and retard mechanism being associated with one of said discs and a centrifugal dwell compensating mechanism being'associated with the other of said discs, said mechanism being adapted to produce a rotational motion of said other discrelative to said one disc whereby the width of said 'slots is increased with increasing speed of rotation of the shaft. 5(An'ignition distributor as claimed in claim 1', wherein the distributor is provided witha removable coil. a

6. An ignition distributor as claimed in claim 1,

1 cap having in it said connecting means and said ignition wherein said means movable in response to changes in the pressure in said manifold is a spring loaded piston arranged around the said shaft, a sleeve surrounding the shaft being connected to the said piston so that axial movement of the piston causes rotational movement of said sleeve about the axis of the shaft, said sleeve constituting part of said connection between the movable means and the light source and photo device.

7. An ignition distributor as claimed in claim 4, wherein the advance and retard mechanism and the dwell compensating mechanism each consist of a pair of weights arranged close to the respective disc and I symmetrically on opposite sides of the axis of the shaft,

movement of the respective disc in relation to the shaft.

8. An ignition distributor as claimed in claim 4, wherein the advance and retard mechanism and the crease in the speed of rotation of said shaft causes each said movable member to move outwardly against the respective inclined surface and thereby deform the respective spring to produce a rotational movement of the respective disc in relation to the shaft.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 767 935 Dated October 23, 1973 Inventor(s) Alan Neville Trass It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, correct the inventor's address as follows:

44 Moyran Parade, Grays Pt. New South Wales In the heading, after line [21] insert the following priority information:

Foreign Application Priority Data February 11, 1971 Great Britain 4460/71 Signed and Sealed this sixteenth Day Of September I 975 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer (ummissiuner ufPaIems and Trademarks 

1. An ignition distributor consisting of a body, a drive shaft supported in the body in bearings, a light source mounted in said body, a photo device mounted adjacent said light source in the path of light therefrom, the light source and the photo device being mounted so as to be movable together about the axis of said drive shaft, a disc mounted on said shaft so that the periphery of the disc rotates between the light source and the photo device there being discontinuities in the peripheral portion of the disc wherebY the path of light from said light source to the photo device is interrupted in a predetermined manner intermittently, centrifugal advance and retard means associated with said disc whereby the disc is rotated in relation to the shaft to an extent related to the speed of rotation of the shaft, a chamber in the body spaced from said disc and adapted to be connected to the inlet manifold of an internal combustion engine, means in said chamber movable in response to changes in the pressure in said manifold when said chamber is connected to said manifold, a connection between said movable means and the light source and the photo device whereby these are moved around said shaft to advance or retard the ignition in relation to said changes in pressure, a distributor arm on said drive shaft, connecting means for connecting an ignition coil to said distributor arm and contact means whereby the electrical output from said ignition coil is delivered in turn to connecting means adapted for connection to the spark plugs of an internal combustion engine.
 2. An ignition distributor as claimed in claim 1, wherein the light source and the photo device are mounted in a fixed relationship in a common housing.
 3. An ignition distributor as claimed in claim 1, wherein a transistorised amplifier trigger unit is mounted within the distributor and means are provided for cooling parts of the distributor adjacent thereto.
 4. An ignition distributor as claimed in claim 1, wherein said disc is made up of two superimposed discs mounted one above the other, having similarly arranged radial slots constituting said discontinuities, centrifugal advance and retard mechanism being associated with one of said discs and a centrifugal dwell compensating mechanism being associated with the other of said discs, said mechanism being adapted to produce a rotational motion of said other disc relative to said one disc whereby the width of said slots is increased with increasing speed of rotation of the shaft.
 5. An ignition distributor as claimed in claim 1, wherein the distributor is provided with a removable cap having in it said connecting means and said ignition coil.
 6. An ignition distributor as claimed in claim 1, wherein said means movable in response to changes in the pressure in said manifold is a spring loaded piston arranged around the said shaft, a sleeve surrounding the shaft being connected to the said piston so that axial movement of the piston causes rotational movement of said sleeve about the axis of the shaft, said sleeve constituting part of said connection between the movable means and the light source and photo device.
 7. An ignition distributor as claimed in claim 4, wherein the advance and retard mechanism and the dwell compensating mechanism each consist of a pair of weights arranged close to the respective disc and symmetrically on opposite sides of the axis of the shaft, each weight being carried on a length of piano wire spring the inner end of which is anchored to the shaft and the outer end of which is connected to the periphery of the disc, the arrangement being such that an increase in the speed of rotation of said shaft produces a deformation of the said spring and thus a rotational movement of the respective disc in relation to the shaft.
 8. An ignition distributor as claimed in claim 4, wherein the advance and retard mechanism and the dwell compensating mechanism each consist of a pair of lengths of piano wire spring connected between the shaft and the periphery of the respective disc, the springs being arranged symmetrically on either side of the shaft, there being associated with each spring a fixed inclined surface and a member movable under centrifugal force, the arragement being such that an increase in the speed of rotation of said shaft causes each said movable member to move outwardly against the respective inclined surface and thereby deform the respective spring to produce a rotational movement of the respective disc in relation to the shaft. 